Call it naivety, but while pondering the capacity of a black tank to utilize on a 62 GT I asked a simple question. How much waste will we need to contain over how long of a time. There was no resource handy to determine how frequent my visits to the dump will be as determined by the capacity of the tanks. For some reason nobody would answer my question about how many gallons of waste a typical user produces over a weekend.
I looked into the average human waste production as determined by body weight and a western diet and I found some interesting facts about the inefficient human digestive system. This is mirrored by the efficiency of plants using photo synthesis at about 10%. While making in buckets in my garage I found the answers to gallons per diem I was looking for, as averaged between my lady and myself. She was a respectable 2.3 gallons and myself 3.1, averaging 2.5gal per person of bio slurry.
Scientific proposals for the conversion of human waste matter into bio gas generators are littered throughout the internet. A small scale version of this fit to the needs of a boon docked motor home would revolutionize the waste management requirements of everyday users while providing a supplemental energy source comparable to solar power.
One should remember that biological waste is full of pathogens and that heat pretreatment (homogenization) is required prior to waste matter entering a digester, the resulting slurry is stored in a tank that introduces organisms that consume the organic matter and produce methane gas. This gas is the used for cooking and heating reducing the need to send your woman out for firewood and minimizes the effects of deforestation.
The heat pretreatment serves another purpose, the remaining effluent that has been through the gas extraction process is suitable to spray on crops. The pathogens are gone and the organic waste has been rendered into fertilizer. It would then be suitable for sale or donation to a farm.
My project is far too modest to undertake this work by myself, my hope in sharing this proposal with the public domain is for the major manufacturers to investigate this process and incorporate what they can into future designs for sustainable waste management. I am sure NASA has a program devoted to this as the space station is a closed environment that requires the extraction of every unit of available energy.
Thank your for your consideration a link to the construction of a simple biogas generator follows.
Design, Construction and Maintenance of a Biogas Generator